Detachable bit tool



Dec. 27, 1955 L. E. AUSTIN 2,728,365

DETACHABLE BIT TOOL Original Filed Dec. 14, 1948 United States Patent DETACHABLE BIT TOOL Leonard E. Austin, South Bend, Ind., assignor to Illinois Tool Works, Chicago, 111., a corporation of Illinois Original application December 14, 1948, Serial No. 65,277,

now Patent No. 2,646,091, dated July 21, 1953. Divided and this application June 5, 1953, Serial No. 359,826

6 Claims. (Cl. 144-32) This invention is a division of my copending application for Power Screw Driver, Serial No. 65,277, filed December 14, 1948, now Patent No. 2,646,091, issued July 21, 1953, and is concerned particularly With a detachable bit tool and a socket for receiving the same.

The broad object of this invention is to provide a power driver having a driving bit which is readily replaceable.

More specifically, it is an object of this invention to provide a power screw driver wherein the bit is readily replaceable for driving different sizes and types of screws.

Another object of this invention is to provide an automatic chuck, a collet, or socket so constructed that a bit may be attached to and detached from a driving mechanism by simple axial insertion and removal of the bit.

A further object of this invention is to provide a separable socket and bit'construction which is simple and economic to fabricate, and which is rugged and substantially foolproof in operation.

Other and further objects and advantages of the present invention will be apparent from the following description when taken in connection with the accompanying drawings wherein:

Fig. 1 is a sectional view of a portion of a power screw driver embodying the principles of my invention;

Fig. 2 is an exploded perspective view of the pertinent parts of the structure shown in Fig. 1; and

Fig. 3 is a cross-sectional view taken along the line 3-3 in Fig. 1.

My aforesaid copending application Serial No. 65,277 discloses a complete power screw driver for automatically feeding screws from a heterogeneous mass into driving position beneath a screw driver bit and for thereafter releasing the screws after they have been driven a predetermined distance. The principles of the invention herein claimed are applicable to screw drivers other than the one shown in my aforesaid copending application and therefore only a part of the screw driver is shown herein. Reference may be had to the aforesaid copending application by those desiring further details on a specific and complete screw driving machine embodying the principles of my invention.

The invention as herein shown and described includes a rotary shaft 10 rotatably journaled by means of ball bearings 12 in a sleeve 14 which is reciprocably mounted in a fixed cylinder or machine part 16. The shaft 10 is provided at its lower end with an enlargement 18 having a cylindrical central bore 20. The bore receives a stub shaft 22 which is held in place by means such as a pair of set screws 24 threaded through the wall or enlargement 18 and bearing against flats 26 on the stub shaft 22.

A hollow cylinder or sleeve 28 is threaded at its upper end into the sleeve 14 at the lower end thereof. The sleeve or cylinder 28 is provided near its upper end and beneath the threaded portion with a circumferential 2,728,365 Patented Dec. 27, 1955 flange 30. A pair of arms 32 of a fork (not shown) mounted for powered reciprocation in a vertical plane lie on opposite sides of the sleeve or cylinder 28 and directly above the flange 30. When the fork is reciprocated by suitable means (not shown) the sleeves 14 and 28 are moved up and down.

The stub shaft 22 is provided intermediate its ends with a threaded portion 34, and a clutch member or collar 36 is splined on the stub shaft just below the threaded section for rotation with the stub shaft, but having relative axial movement along the shaft. The clutch member 36 has its lower face provided with teeth or projections 38 adapted to engage complementary notches formed by similar teeth 40 on the upper face of a clutch member or collar 42. The clutch member or collar 42 is rotatably mounted on the stub shaft 22 but is held against movement axially of the shaft by ball bearings 44 received in a groove 45 at the lower end of the shaft and in a confronting groove in the'inner surface of the collar 42. The ball bearings are inserted through a radial opening 46 in the collar 42, and that opening is closed after insertion of the ball bearings by a set screw 48 threaded into the opening. The set screw 48 is locked in position by a wire ring 50 received in an annular slot or groove 52 in the collar 42 and in a driving slot in the set screw.

The clutch member or collar 36 is urged into driving engagement with the clutch member or collar 42 by a coil spring 54 interposed between a shoulder 56 of the clutch member 36 and a ring or washer 58 encircling the stub shaft 22. The ring or washer 58 is formed with an inwardly directed radial key or lug 60 which is received in a key slot 204 in the threaded section 34 of the stub shaft 22. The ring or washer 58 is adjusted axially along the stub shaft 22 and is held against axial movement by a ring nut 64 threaded on the threaded section 34 of the stub shaft. 'The ring or washer 58 is formed with upwardly extending knobs or projections 66 received in complementary radial notches 68 in the under surface of the ring nut 64. Itwill be apparent that the keying of the ring or washer 58 to the stub shaft and the splining of the clutch member 36 on the stub shaft insure rotation of the clutch spring 54with the stub shaft so that the spring exerts no drag on the rotation of the stub shaft. The ringor washer 58 also acts to hold the adjusting nut 64 in adjusted position.

The clutch member 42, in addition to the clutch teeth 40 on its upper surface, is provided with a pair of diametrically spaced, substantially V-shaped, clutch teeth 70 on its lower surface. These teeth are adapted for cooperation with teeth 72 of similar disposition and configuration on the upper surface of a third clutch member or collar 74. i

The third clutch member or collar 74 is mounted on a tool receiving chuck or collet 76 which consists of a stub shaft having a reduced upper portion 78 received in an axial bore 80 in the lower portion of the stub shaft 22. The reduced shaft portion 78 and bore 80 are of proper relative diameters to form a close frictional fit.

the upper end of the reduced shaft portion 78.

The tool receiving chuck or collet 76 is formed with a ring portion or annular flange 84 on which the clutch member 74 is press fitted. The clutch member 74 is keyed to the chuck or collet 76 by a flange 86 on the chuck or collet, the flange having opposed fiat surfaces 88 and being fitted in a cross slot 90 in the lower face of the clutch member 74 with the fiat surfaces 88 engaging the flat sides of the'slot 90.

It will be understood that in place of the double clutch between the driving shaft and tool receiving chuck or A coil; spring 82 is compressed in the bore 80 and bears against .5 collet as described above, any standard or known double clutch functioning in a similar manner may be used.

The lower end of the chuck or collet is reduced in diameter as at 92,thereby forming a small annular shoul, der 94 between the reduced portion and an intermediate larger portion 96. The chuck or collet is also formed at its lower end with a hexagonal axial aperture 98 opening at the lower end of the reduced portion 92. The reduced portion 92 further includes a radial opening 100 which is shaped or countersunk to receive a ball, key or pin 102 resiliently pressed into the hexagonal opening 98 by a split ring spring retainer 104 having a hole 106 therein engageable with the ball 100 to preclude shifting of the ring to bring the slot therein into alignment with the ball.

The inwardly urged ball 102 detachably retains a driver bit 108. The driver bit comprises a rod 110 having an enlarged portion 112 at its lower end, and hexagonal portions 114 and 116 at its upper end spaced apart by an annular groove 118. The rod is also provided with an enlarged portion or protuberance 120 immediately below the hexagonal section 116 and larger than the hexagonal opening or bore 98 in the chuck or collet 76, so that engagement of the protuberance 120 against the lower end of the chuck or collet 76 positions the annular groove in the plane of the retaining ball, pin, or key 102 which is urged part way into the groove by the split ring spring retainer 104 detachably to retain the bit 108 in the chuck or collet.

The enlarged portion 112 of the driver bit is provided at its lower end with a threaded bore 122 which detachably receives a driver blade 124 having a threaded reduced upper end portion 126 thereon. The screw engaging and driving end of the driver blade 124 may take any of a number of different forms depending upon the head shape of the various screws which it is desired to handle. In general, the screw engaging and driving end of the driver blade is formed with a flat sided projection or blade 128. adapted to engage within the driving slot of a screw. The bottom of the blade 124 in addition to the flat sided projection 128 preferably is formed complementary to the shape of the head of a screw to be driven, and for illustrative purposes the under side of the blade 124 may be concave for driving round headed screws.

The sleeve or cylinder 28 is internally threaded at its lower end with left-hand threads as at 130. A sleeve nut 132 is externally threaded with left-hand threads for cooperation with the threads 130 to preclude loosening of the nut by rotation of the tool receiving chuck or collet. The sleeve nut 132 is provided in its inner surface with needle bearings 134 which rotatabl'y journal the intermediate portion 96 of the tool receiving chuck or collet 76. The sleeve nut also serves as an abutment limiting the axial movement of the clutch member 74 in a direction away from clutch member 42. The frictional fit of the reduced shaft portion 78 inthe bore 80, and the spring 82 serve frictionally to start driving of the tool receiving chuck or collet 108 as the clutch members 42 and 74 move toward one another for driving engagement.

The sleeve or cylinder 28 is provided with an opening 136 opposite the threaded portion 34 of the stub shaft 22 for adjusting the ring nut 64. The ring nut is externally knurled, or may be provided with circumferentially spaced holes for cooperation with a tool which may be inserted through the opening 136 to rotate the nut. Such rotation of the nut adjusts the pressure exerted by the spring 54 on the clutch member or collar 42, such rotation most readily being effected by holding the nut with the tool while manually turning the spindle of the power driver to rotate the shaft and hence the stub shaft 22. This determines the torque at which the clutch member 36may move out of engagement with the clutch member 42.

Means is provided for carrying screws in cooperation with the structure heretofore disclosed and includes a sleeve on cylinder 138 reciprocably mounted about the sleeve or cylinder 28. The cylinder 138 is formed adjacent its upper edge with a peripheral ring 140 having a square lower shoulder 142 and a beveled upper shoulder 144. A split ring 146 is clamped on the sleeve or cylinder 28 above the top or sleeve of the cylinder 138 by any suitable or known means such as a screw 148. The ring 146 includes a pair of spaced apart ears 150 having a pin 152 extending between them and pivotally carrying a hook 154. The hook includes a tooth 156 having a pair of beveled working edges, and a tooth 158 having a square shouldered upper work engaging edge. The hook 154 further includes a lug 160 having a curved cam surface 162.

A bracket 164 is provided with a ring-like portion 166 encircling the sleeve or cylinder 14, and this ring-like part is secured by means such as countersunk bolts 168 to the under side of the fixed cylinder or machine part 16. The bracket 164 is provided with a depending part 170 having a vertical flange 172 through which pass bolts or screws 174. adjustably to hold a control memher 176 in operative position. The control member 176 includes a cam edge 178 cooperable with the protuberance. 160 on the hook 154 to maintain the. same in engagement with the flange 140 substantially as shown in Fig. 1. The cam surface is cut back diagonally as at 180 into a depending armv 182 on the control member.

The sleeve or cylinder 138 is provided with a threaded, reduced. lower end 184. A'screw receiving and positioning means comprises a split sleeve 186 and has a circumferential flange 188 at its upper end which is held against the bottom end of the reduced portion 184 by a nut 190 threaded. on this portion and having an inwardly directed flange 1 92 underlying the flange 188 on the screw receiving means. The screw receiving sleeve 186 is provided with a pair of longitudinal slits 194 extending substantially from end to end and each slit at the upper end thereof terminates in an enlarged opening 196. The two halves of the sleeve 186 are provided along one of the slits 194 with a cut-away portion 198 for permitting passage of a screw head between the arms. Inwardly directed lips or fingers 200 are designed to support the head of the screw with the shank thereof extending out between the lips.

The arm 182 is provided at its lower end with a cylindrical portion 202 through which the split sleeve 186 and bit 108 extend. A- bushing or liner 204 having a head or flange 206 is fitted in the cylindrical portion 202 and holds; the arms of the split sleeve 186 in the position shown, these arms being resilient and biased so as to tend to spring apart from one another. A lubricating ring 208' may be fitted in a suitable: groove in the inner face of the bushing 204 for lubricating the external surface: of the split sleeve to reduce friction between the split sleeve and the bushing 204. The bushing is held inplace by a spring wire 208 having a finger portion 210, all as explainedin detail in my aforesaid copending application Serial No. 65,277. In the event that a screw should fam between the arms of the split sleeve 186, or between the arms or driver blade184, the bushing 204 may be removed by pulling on the finger grip 210 toretract the wire 208 and raising the bushing.

The split sleeve 186 is compieted' by enlargements 212 normally positioned above the bushing 204.

In the operation of the screw driving machine herein shown in part and more fully described in my aforesaid copending application Serial No. 65,277, a screw is fed from a hopper down a screw feeding chute (not shown) and through the opening 198 into position between the halves of the split sleeve 186 where the screw is supported in alignment with the driver blade 124 by the lips 200 fitting beneath the head of the screw, the shank of the screw protruding outwardly beyond the screw carrier or split sleeve 186. Suitable mechanism (not shown) is'provided which, inresponse to depression of a foot pedal or the like by an operator; lowers the fork arms 32; and thereby lowers the sieeve 28 and also the sleeve 14 and shaft 10. The split sleeve 136 and cylinder 138 are frictionally supported in the position shown in Fig. 1. Such downward movement of the shaft it) lowers the bit 198 and driver blade 124 until the blade projection 128 engages a screw head. The reduced shaft '73 and the driver blade connected thereto are rotated by the frictional fit of the shaft 78 in the bore 89 of the stub shaft 22, and also by engagement of the spring 82 with the reduced shaft '78. Continued rotation and downward movement of the shaft 1% causes the blade projection 128 to engage in the driving slot of the screw and causes the clutch member 42 to move into driving engagement with the clutch member 74, thereby positively driving the chuck or collet 76, the bit Hi2, and the driver blade 124. At this time the lower surface of the tooth 56 engages the beveled surface 144 of the flange 140 to shift the cylinder 138 and screw receiving means or split sleeve 186 downwardly with a screw as it is screwed into a work piece.

After the screw has been screwed part way into a work piece, the lug 160 reaches the cut-back portion 130 of the cam surface 178 so that the hook is free to move out away from the flange 140 under the camming action of the upper surface 144 of the cam 140 and the lower surface of the tooth 156. Thus the screw carrier or split sleeve 186 is no longer lowered, but by this time the enlar ements or protuberances 212 on the sleeve have passed through the bushing 204 so that the halves of the sleeve are free to move away from one another under their own outward bias. The screw head therefore is freed of restraint so that the screw may be driven home without damage to, or marring of the screw or work piece.

in returning the parts, the operation is substantially the opposite. The tooth 156 cams past the flange 140, but by the time the tooth 158 reaches the flange 140, the cam surface 162 of the lug 160 has ridden in on the cutback 189 of the cam 178 so that the tooth 158 is caught beneath the square shoulder 142 of the flange 140 and the parts are retracted to the position shown. It will be evident that the drive bit blades 124 are readily detachable from and insertable in the shanks of the driver bits so that a single shank may be used with any one of a large variety of bit blades differing in size and in the shape of their screw receiving ends to handle a large variety of types and sizes of screws without requiring any change other than in the bit blade. It will be evident, however, that it may be desirable in a large number of cases to handle screws of types and sizes outside of that range which can be conveniently handled by insertion of driver bits in a single size bit shank. Therefore, the bit shank itself is readily detachable from and insertable in the tool receiving chuck or collet. Such detachment and insertion is readily accomplished by axial force imposed on the shank by the hand of the operator. The means for detachably holding the bit shank in place is relatively foolproof in operation and is simple and economical to fabricate, while being rugged in operation.

It will be understood that the specific example herein shown and described is for illustrative purposes only. The detachable bit tool can be used with other types of screw drivers, and the tool may vary structurally within the spirit and scope of the appended claims.

I claim:

1. A detachable bit tool comprising a rotary fastener driver receiving collet having a bore of non-circular shape to receive a complementary shaped end of a rotary fastener driver bit, said bore communicating with a transverse passage, a rotary fastener driver retaining latch member mounted in said passage and projectable into the bore to engage and retain a rotary fastener driver bit inserted into the bore, a split spring ring retainer encircling said collet and covering said passage to urge said latch member into said bore, needle bearin means for rotatably mounting said collet in a power machine, and means on said collet engaging said bearing means to limit axial movement of said collet in said bearing means while allowing axial movement in the opposite direction.

2. A detachable bit tool as set forth in claim 1 wherein the limiting means comprises a clutch member engageable with a driving clutch member on a power machine for rotatably driving said rotary fastener driver.

3. A detachable bit tool comprising a threaded plug adapted to be threaded into engagement with a complementary threaded portion of a power machine, antifriction bearing means in said plug,-and a collet rotatably journaled in said anti-friction bearing means, said collet having a bore of non-circular shape to receive a complementary shaped end of a rotary fastener driver bit communicating with a transverse passage in said collet, a rotary fastener driver retaining latch member mounted in said passage and projecting into the bore to engage and retain a rotary fastener driver bit in the bore, and an elastic retainer encircling said collet and covering said passage for resiliently urging said latch member into said bore.

4. A detachable bit tool as set forth in claim 3 wherein the collet is provided with a clutch member engageable with a complementary clutch member on a power machine, the collet is axially movable in the bearing means, and said clutch member engages said bearing means to limit axial movement in one direction.

5. A detachable bit tool comprising a rotary fastener driver receiving collet having a bore of non-circular shape to receive a complementary shaped end of a rotary fastener driver bit, said bore communicating with a transverse passage, a rotary fastener driver bit retaining latch member mounted in said passage, an elastic retainer encircling said collect and covering said passage, said retainer resiliently projecting said latch member into the bore to engage and retain a rotary fastener driver bit inserted into the bore, a substantially cylindrical sleeve coaxial with said bore and projecting a substantial distance forwardly from said collet, said sleeve having a diameter which is small relative to its length, and a rotary fastener driver bit cooperable with said collet and with said sleeve, said bit having a non-circular end portion received in said bore and having a shank projecting axially from said bore on the same order of distance as said sleeve, a substantial portion of said shank having a small diameter compared of said bit having a diameter on the same order of magnitude as that of said sleeve.

bit tool comprising a rotary fastener driver receiving collet having a bore of non-circular shape References Cited in the file of this patent UNITED STATES PATENTS 722,324 Pitkin Mar. 10, 1903 1,391,177 Du Sell Sept. 20, 1921 1,742,040 Lynch et al. Dec. 31, 1929 1,952,395 Tillyer et al Mar. 27, 1934 2,394,348 Wilhide Feb. 5, 1946 2,472,392 Alexander June 7, 1949 2,484,364 Whitledge Oct. 11, 1949 

